Lithium Battery set up

[Rockpool]

Question that probably been asked a million times but Looking for your thoughts. I have a pair of 110ah lead acid batteries and one of them is not holding charge. So have been debating with myself for a few months on going down the lithium route. So not wanting to open a can of worms I’ve been looking at a set up that we think suits our needs which I've attached below.

As we mainly wild camp all year round, have found that our 285W of solar is not enough to keep the batteries charged up in the winter so thinking B2B is the way forward. The inverter, thinking as it also includes an ac-dc battery charger (need a new battery charger anyway as the EC 500 Sargent panel on board won't cope with lithium) might be a good idea? Save space and cabling.

Equipment:

• Pair of 100Amp Renogy Lithium Batteries.
• 2000W 12v pure sine Renogy inverter/battery charger.
• 12V 60Amp B2B Renogy Charger. (not sure if we should go for a 40amp instead as not 100% sure of the alternator size as cant find the label on it and its tucked away under plastic shrouding our van is a Fiat Ducato 2.3 maxi 2017)
• Duoracer 30amp solar MPPT (existing)
• Planning to use the Renogy BT-2 along with the communication hub to hopefully allow everything to be monitored.

Thinking of making and installing a bus bar to make the connections easier and neater I hope along with using Mega Fuses at the bus bar connection.

Cable sizes noted as recommended by Renogy.

So any thoughts on the layout would be appreciated as iam no expert by any means but enjoy the challenge

 

[Raul]

It’s allot of data there, I spotted one thing: batteries needs fusing individually to the buss bar. Use a distribution or holder for mega and midi, don’t use the fuse as a hardware connection, they are on not strong enough under vibration. Something like this.

Also, solar panels, what size? If you have space, go for 1x1,6m 60 cell panels. Robust long lasting and efficient. You can go as high as 380w on single panel.

 

[Rockpool]

Thanks Raul for that good point on the fuses.
we have got 280w solar on the roof and don’t have any more space.

 

[suavecarve]

I have been in somewhat a similar quandary.
I am holding off the lithium battery atm because I suspect they will be cheaper later in the year (Owing to Chinese rights)
The questions I would be asking myself, if I were you would be,

If I have been ok with 2 x 110 ah lead acid, why do i need 200 ah of lithium to replace them and if I do then why do i need them in 2 separate batteries when it would be cheaper to buy one 200 ah lithium
Am I better off buying one 110ah lead acid replacement and seeing if the lithium become cheaper later in the year but sort everything out like the MPPT and B2B in the meantime so it will be a drop in?

Food for thought hopefully

 

[Tombola]

have a a look at KS energy with the funster discount code on the batteries.
200ah with bms app, £926
I have the Renogy Inverter 2000w and does my toaster, kettle and micro no problem (small mic)
kettle draws 1000 toaster 7-800 Mic bursts but then settles fine.
Does your Autotrail have a smart alternator, My autotrial on a fiat was 2019 and surprisingly didnt.
I seen the renogy review of the b2b a while back but I stuck with the victron

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[Rockpool]

Yes have looked at both the 1x 200ah or 2 x 100ah, the reason for me was the 100ah fit in better with the van layout at present and for some reason the 100ah batteries have 4000 cycles at 80% where the 200ah have only 3000 cycles at 80%. So have quierd this with Renogy but they haven’t replyEd yet?
on the lead acid due mostly wild camping when getting into the colder months we were struggling with the batteries so theory behind it as thinking of upgrading go for 200ah which lets us use up to 80% and install an inverter which the lead acid would struggle with.

 

[Rockpool]

have a a look at KS energy with the funster discount code on the batteries.
200ah with bms app, £926
I have the Renogy Inverter 2000w and does my toaster, kettle and micro no problem (small mic)
kettle draws 1000 toaster 7-800 Mic bursts but then settles fine.
Does your Autotrail have a smart alternator, My autotrial on a fiat was 2019 and surprisingly didnt.
I seen the renogy review of the b2b a while back but I stuck with the victron

Thanks for that. Don’t think my Autotrail has a smart battery. Looked at KS energy batteries but thinking the100ah fit my set up better at the moment. And not very much difference in cost between the two. On your B2b what size did you install? aim still undecided between the 40 or 60amp.

 

[Tombola]

Thanks for that. Don’t think my Autotrail has a smart battery. Looked at KS energy batteries but thinking the100ah fit my set up better at the moment. And not very much difference in cost between the two. On your B2b what size did you install? aim still undecided between the 40 or 60amp.

I installed the 30 on the autotrail did ok tbf alongside the solar.
It put in more then 30 sometimes 38 -40 according to the bms.

What sort of amps does your alternator throw in now, do you know, my autotrail was doing a measly 7 ampsm after learning on here the weedy wiring chokes it.

The Rapido I have now the alternator send 40+ amps, down the 16mm cables, I have the Victon B2b but it looks like it isnt needed

 

[Lenny HB]

still undecided between the 40 or 60amp.

I doubt if you have an uprated alternator in an Autotrail so I would stick with the 40 amp

 

[Rockpool]

I installed the 30 on the autotrail did ok tbf alongside the solar.
It put in more then 30 sometimes 38 -40 according to the bms.

What sort of amps does your alternator throw in now, do you know, my autotrail was doing a measly 7 ampsm after learning on here the weedy wiring chokes it.

The Rapido I have now the alternator send 40+ amps, down the 16mm cables, I have the Victon B2b but it looks like it isnt needed

Not sure what the alternator is throwing in, will need to investigate that? But by the size of the cables not very much

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[bigtwin]

If you’re running an inverter, be mindful of the potential maximum current draw. In some cases, two lower capacity batteries have a greater maximum output current than a single large capacity battery.

Ian

 

[autorouter]

Thinking of making and installing a bus bar to make the connections easier and neater I hope along with using Mega Fuses at the bus bar connection.

Just a detail before you actually start buying stuff. You'll struggle to find a Mega fuse less than 100A, you need Midi fuses, very similar but smaller, available down to 30A.

You might want something like this, as in Raul's photo

Mega & Midi Fuse Power Distribution Box

Compact power distribution & fuse box that distributes power theough a single mega link fuse into 4 midi or strip link fuses.

www.12voltplanet.co.uk

Also I notice there's no temperature sensor from the B2B to the lithium battery. If it gets the data via Bluetooth then that's OK, but if not it needs something to stop it charging below zero.

 

[Lenny HB]

Not sure what the alternator is throwing in, will need to investigate that? But by the size of the cables not very much

Regardless of alternator size Brit vans always use well undersized cables that why the standard split charge systems are so poor.

 

[Tombola]

Regardless of alternator size Brit vans always use well undersized cables that why the standard split charge systems are so poor.

Ill bet a pound to a pinch of Dog *** that its no more than 8 amp

 

[Rockpool]

Just a detail before you actually start buying stuff. You'll struggle to find a Mega fuse less than 100A, you need Midi fuses, very similar but smaller, available down to 30A.

You might want something like this, as in Raul's photo

Mega & Midi Fuse Power Distribution Box

Compact power distribution & fuse box that distributes power theough a single mega link fuse into 4 midi or strip link fuses.

www.12voltplanet.co.uk

Also I notice there's no temperature sensor from the B2B to the lithium battery. If it gets the data via Bluetooth then that's OK, but if not it needs something to stop it charging below zero.

thanks autoroutes have had a look at the fuse holder and this looks perfect for the install. Have been looking into B2b regarding low temperature cut off and could only find the Sterling B2b with low temp connection looking at the victron 12-12-30 this doesn’t seem to come with a low temp cut off so not sure if it this gets info via Bluetooth? As batteries mounted inside van and looking at fitting some sort of heat pads which might solve the problem of low temp.

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[gerry mcg]

The votronic <Broken link removed> B2B definitely has a wired temp sensor (it wont charge on lithium setting without it), as does the Votronic VCC-121230.
Reading the victron forum, the the Victron Orion B2B cannot at present get the temp via BT, even if you have a Victron SmartBatterySense (SBS) that broadcasts Temp and voltage info (that can BT connect to a Victron SmartSolar MPPT and this will tell the MPPT to stop charging lithium below a set temp.

the absence of temperature sensor or ability to connect to a VE.network that has a SBS on it would appear to be a significant shortcoming with the victron Orion 12-12-30 B2B at the moment

Is there LiFePo4 low temperature charging protection for Orion-Tr DC-DC and MultiPlus? - VictronEnergy

community.victronenergy.com

 

[Raul]

Victron Orion B2B does not have cold tem protection. You will have to have external protection, or go Sterling. I use Orion without. My B2B is ignition triggered but with a switch. I switch off when cold or not needed. Over 7-8 months of the year I don’t use B2B at all, only solar.

 

[Tombola]

I switch off when cold or not needed

same here.

Also OP, didnt you say you were keeping your batteries inside, ?? so do you need a temp sensor as once charged to 80% lithium will last a good while.
PLUS if you are buying the ones with a bms, like I have from KS Energy the BMS will not allow charge at low temps anyway

 

[Raul]

thanks autoroutes have had a look at the fuse holder and this looks perfect for the install. Have been looking into B2b regarding low temperature cut off and could only find the Sterling B2b with low temp connection looking at the victron 12-12-30 this doesn’t seem to come with a low temp cut off so not sure if it this gets info via Bluetooth? As batteries mounted inside van and looking at fitting some sort of heat pads which might solve the problem of low temp.

Just a note, if you do go for that holder, buy extra 15x3 copper bar and beef it up. The existing one is pants 12x1mm at best. I added two 15x3mm bought 150mm length on eBay for few pennies.

 

[Dave101]

Not much to add, but something that surprised me about the Renogy 100ah batteries when I was looking around a few months ago was that they make use of pouch cells in the current UK versions (heated or non heated), most manufacturers seem to use either cylindrical or prismatic cells.

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[Rockpool]

Not much to add, but something that surprised me about the Renogy 100ah batteries when I was looking around a few months ago was that they make use of pouch cells in the current UK versions (heated or non heated), most manufacturers seem to use either cylindrical or prismatic cells.

Interesting didn’t know that. More homework

 

[two]

I'd go for one big battery rather than two smaller ones because I'm not sure how well two separate battery management systems would behave. Not all BMS perform the same and I wouldn't expect reduced price solutions to address this as elegantly as their more expensive cousins. (How can they balance, for example, without information from the other bank?)
Maybe you don't need such a large capacity anyway?

 

[Dave101]

Interesting didn’t that. More homework

PS, I didn't get them so can't comment on their performance, I opted for the KS 200ah seatbase in the end.

 

[cmcardle75]

I'd definitely go after a single large battery than two separates. The only reason I'd go for separates are a later addition, or installation issues. You get into a whole world of balancing not only between cells, but also between the batteries.

I guess you really need the inverter? I wouldn't bother. However, I know some people have partners with hairdryer fixations, or the desperate need for a microwave, which forces the issue.

 

[Rockpool]

PS, I didn't get them so can't comment on their performance, I opted for the KS 200ah seatbase in the end.

Very interesting video.

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[Raul]

I'd go for one big battery rather than two smaller ones because I'm not sure how well two separate battery management systems would behave. Not all BMS perform the same and I wouldn't expect reduced price solutions to address this as elegantly as their more expensive cousins. (How can they balance, for example, without information from the other bank?)
Maybe you don't need such a large capacity anyway?

They don’t need to balance with each other, they share same voltage and each bms caters for each pack. Victron recomends on their batteries with bms inside “ parallel unlimited”. In fact there are advantages of multiple parallel. Each are managed by their bms, discharge/ charge limits are higher cumulative, redundancy, any faulty will shut down without hindering the work of others, better use of confined limited spaces, lots of advantages, and no disadvantages at all. I run two in parallel since 2019, and many do as well. Even the cheapest Chinese low cost you can run 4 parallel. Nothing to worry from this point of view.

 

[Raul]

I'd definitely go after a single large battery than two separates. The only reason I'd go for separates are a later addition, or installation issues. You get into a whole world of balancing not only between cells, but also between the batteries.

I guess you really need the inverter? I wouldn't bother. However, I know some people have partners with hairdryer fixations, or the desperate need for a microwave, which forces the issue.

Larger batteries are made by multiple parallel cells inside, controlled by a single bms. By halving the cell count and adding a bms, the cells are better protected and controlled. The less cells per bms the better.

 

[cyberyacht]

If using an inverter for heavy loads, having two batteries in parallel halves the amperage draw on each battery which must be kinder to them.

 

[ManTheVan]

I suppose it depends on your power demands.

I believe our panel is either 100W or maybe slightly more (it was on the MH when we bought it and I can’t find the rating without taking it off to look underneath), but with a 100Ah Ultramax LiFePO4, Sterling 30A B2B and Victron smartsolar mppt, we have not yet had to use shore power. We fitted a 2kw sine wave inverter which is mainly used for charging e-bike batteries and I made sure that all the lighting is warm white LED.

According to the Victron shunt, the largest power draw comes when we have the extractor on over the hob (approx 33W).

What I mean by all this is that you might well be able to save some money by having only one battery, even if you update the capacity a bit.

 

[Lenny HB]

If using an inverter for heavy loads, having two batteries in parallel halves the amperage draw on each battery which must be kinder to them.

Probably doesn't make a lot of odds. A battery twice the size will either have double the number of cells or larger cells that can stand a higher current load.

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